Most people have had their blood pressure checked at some point. During a routine visit, a cuff is wrapped around the arm, it tightens for a few seconds, and then two numbers appear on the screen.
Many people know that these numbers are important because they help doctors understand heart health. However, new research suggests that one of these numbers may also provide important clues about the health of the brain.
A study led by researchers at the University of Miami has found that the second blood pressure number, known as diastolic blood pressure, may play a larger role in brain health than many people realize.
The research, led by Michelle R. Caunca and published in the journal Stroke, suggests that keeping this number within a healthy range could help protect the brain as people age.
Blood pressure readings contain two numbers. The first number, called systolic blood pressure, measures the pressure in the arteries when the heart is actively pumping blood.
The second number, called diastolic blood pressure, measures the pressure in the arteries when the heart relaxes between beats. For many years, doctors have focused heavily on the systolic number because it is strongly linked to heart attacks, strokes, and other cardiovascular diseases.
However, the new study suggests that the diastolic number deserves more attention. Researchers wanted to understand whether this measurement was linked to changes in the brain that occur with aging.
The research team examined 1,205 adults aged 50 and older. Participants underwent MRI brain scans that allowed scientists to look for tiny areas of damage known as white matter lesions. These lesions are small scars that develop in the brain’s white matter, the network of nerve fibers that allows different parts of the brain to communicate with each other.
Most people do not notice these lesions because they do not cause immediate symptoms. However, over time, they can affect important brain functions. Previous studies have linked white matter lesions to memory problems, slower thinking, difficulties with movement, balance issues, a higher risk of falls, and an increased chance of stroke.
When the researchers compared blood pressure levels with MRI results, they discovered a clear pattern. Individuals with lower diastolic blood pressure, generally below 80 millimeters of mercury (mmHg), tended to have fewer white matter lesions.
In contrast, people whose diastolic blood pressure was above 90 mmHg were more likely to have a greater amount of brain damage visible on their scans.
This finding suggests that elevated diastolic blood pressure may slowly damage blood vessels in the brain over many years. The damage can accumulate silently, often without any obvious warning signs, until it eventually begins to affect thinking, memory, or physical function.
White matter plays a vital role in keeping the brain working efficiently. It acts like a communication network, carrying messages between different brain regions. When white matter becomes damaged, these signals can become slower or disrupted.
As a result, everyday tasks that rely on memory, decision-making, attention, or movement may become more difficult.
The researchers also found that the location of these lesions matters. In particular, damage occurring in a deep brain region known as the periventricular area appeared especially important. Lesions in this region have been linked to cognitive decline, memory difficulties, and other problems associated with aging.
White matter lesions become increasingly common as people get older. Research suggests that by the age of 60, as many as one in five adults may already have evidence of these changes. The number continues to rise with age. By the time people reach their nineties, most will have at least some degree of white matter damage.
The good news is that blood pressure is one of the factors people can often manage.
Lifestyle choices such as regular exercise, maintaining a healthy weight, eating a balanced diet, reducing salt intake, avoiding smoking, limiting excessive alcohol consumption, and managing stress can all help support healthy blood pressure levels. When needed, medications can also help keep blood pressure under control.
The findings highlight the importance of paying attention to both numbers in a blood pressure reading.
While the top number remains an important measure of heart health, the bottom number may provide valuable information about brain health as well. A healthy diastolic blood pressure may help reduce the risk of silent brain damage that can accumulate over time.
The study does not prove that higher diastolic blood pressure directly causes white matter lesions, but it provides strong evidence of a significant connection between the two. More research will be needed to fully understand the relationship and determine the best ways to protect brain health through blood pressure management.
For now, the message is simple. When checking blood pressure, it may be worth paying attention not only to the top number but also to the bottom one. That small number could offer important clues about how well the brain is aging and may help people take steps to protect their memory, thinking abilities, and quality of life in the years ahead.
If you care about high blood pressure, please read studies that early time-restricted eating could help improve blood pressure, and natural coconut sugar could help reduce blood pressure and artery stiffness.
For more health information, please see recent studies about added sugar in your diet linked to higher blood pressure, and results showing vitamin D could improve blood pressure in people with diabetes.
The research was led by Michelle R. Caunca and published in the journal Stroke.
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